Establishing an Ion-Sieving Separator by Depositing Oxygen-Deficient SiO_x Layer for Stabilized Zinc Metal Anode

Stable plating/stripping of Zn metal anode remains a great challenge owing to uncontrollable dendrite growth and side reactions. Ion-sieving separators is a unique and promising solution, that possess Zn²⁺ permeability and promote Zn²⁺ transport, can effectively alleviate the abovementioned problems. Ion-sieving on glass fiber separator by deposition of oxygen-deficient SiO_x layer via active screen plasma technology is achieved. While having chemical composition similar to the glass fiber, the SiO_x nanoparticles contain oxygen-rich vacancies that promoted dissociation of the adsorbed water and generation of the hydroxyl groups. The negatively-charged hydroxylated SiO_x layer can repel SO₄ ^2- and attract Zn²⁺, which can alleviate the side reactions. The strong interplay between hydroxyl groups and Zn²⁺ can boost Zn affinity and yield fast Zn²⁺ transport. Consequently, the SiO_x-deposited GF separator enabled dendrite-free Zn deposition morphology, which displays lower overpotential of 18 mV and longer cycling life over 2000 h for Zn symmetric cell. Such a separator can also be easily scaled up to prepare the high-performance large-area (4 × 6 cm²) pouch Zn-based devices, showing remarkable flexibility and practicality.